Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932607AbWIVRCB (ORCPT ); Fri, 22 Sep 2006 13:02:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932600AbWIVRCB (ORCPT ); Fri, 22 Sep 2006 13:02:01 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:56742 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S932603AbWIVRCA (ORCPT ); Fri, 22 Sep 2006 13:02:00 -0400 Date: Fri, 22 Sep 2006 18:53:52 +0200 From: Ingo Molnar To: Mathieu Desnoyers Cc: Martin Bligh , "Frank Ch. Eigler" , Masami Hiramatsu , prasanna@in.ibm.com, Andrew Morton , Paul Mundt , linux-kernel , Jes Sorensen , Tom Zanussi , Richard J Moore , Michel Dagenais , Christoph Hellwig , Greg Kroah-Hartman , Thomas Gleixner , William Cohen , ltt-dev@shafik.org, systemtap@sources.redhat.com, Alan Cox Subject: Re: [PATCH] Linux Kernel Markers 0.5 for Linux 2.6.17 (with probe management) Message-ID: <20060922165352.GA16476@elte.hu> References: <20060921160009.GA30115@Krystal> <20060921160656.GA24774@elte.hu> <20060921214248.GA10097@Krystal> <20060922064955.GA4167@elte.hu> <20060922140329.GA20839@Krystal> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060922140329.GA20839@Krystal> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -2.9 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.9 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.5 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.4983] -0.1 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1302 Lines: 37 * Mathieu Desnoyers wrote: > > > Then you lose the ability to trace in-kernel minor page faults. > > > > that's wrong, minor pagefaults go through __handle_mm_fault() just as > > much. > > > > Hi Ingo, > > On a 2.6.17 kernel tree : > It seems like a shortcut path that will never call __handle_mm_fault. > This path is precisely used to handle vmalloc faults. yes, but you said "minor fault", not "vmalloc fault". minor faults are the things that happen when a task does read-after-COW or read-mmap-ed-pagecache-page, and they very much go through __handle_mm_fault(). vmalloc faults are extremely rare, x86-specific and they are a pure kernel-internal matter. (I'd never want to trace them, especially if it pushes tracepoints into every architecture's page fault handler. I implemented the initial version of them IIRC, but my memory fails precisely why. I think it was 4:4 related, but i'm unsure.) (i now realize that above you said "in-kernel minor faults" - under that you meant vmalloc faults?) Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/